Many of us use headphones while working out, but what is the best choice for you? Before head-fi I used to use Sony folding sport headphones for my workouts (weights and bike/treadmill). Over time the tiny holes would clog, I would clean them, and repeat, but every 6 months or so the sound quality would suffer and I would buy a replacement (and you can call me sir-sweats-a-lot during those intense 2 hour workouts 4-5 days a week of yesteryear). Once I found head-fi I started using IEMs. They work well at the beginning of my workouts, but as my workouts go to the end the repeated removal/insertion between sets along with my sweat would cause the IEM to lose it's seal. When I started to wear the cable over my ears it helped a little, but didn’t totally resolve the issue. Luckily I have not seen any cable issues from sweat when wearing them with the cables over my ears. My wife runs as well as uses weights and the treadmill and has been using the ADDIEM with foam Shure olives as silicon tips kept falling out of her ears (and I mean completely out). A few of her thoughts are also included.

The CX 680 Sports ($89 on Amazon) is an in ear headphone with earfins and the PMX 680 Sports ($54 on Amazon) is a headphone with a behind the neck band. Sennheiser has partnered with Adidas, and both brands are marked on the packaging, headphones, and all accessories. The accessories included are nice, especially the carrying pouches. The look of these definitely screams workout, and the carrying cases seem to fit the part also, but would look good in most settings!

(Clip shown for size, cleaning tool not pictured and only one extension cable as they are both the same)

Both come with nice accessories including a detachable extension cable with volume control which has a recessed jack that holds the headphone plug in firmly, but will separate if the cable catches on something. The CX has 3 sizes of ear tips and three sizes of ear fins plus a cover for where the earfins attach if you chose not to use them. Build quality seems very good and aside from stepping on them or dropping a heavy weight on them, they seem like they will be able to keep up with the rigors of workouts.

Both have good manuals, especially the CX, which has fantastic instructions on how to install the fins and wear the IEM in many languages. The CX also has replaceable “diaphragm guards” which are little pieces of foam that go in the nozzle to protect the driver. There is one replacement set (in the bag in the picture), but I am sure Sennheiser would be happy to send you more if you asked. The PMX uses the small holes similar to what my old Sony foldable workout headphones had, so there is the chance they will get plugged over time like happened with my Sony’s (if you sweat a lot).

Fit and Comfort: My wife and I differed on which was more comfortable and had a better fit. I thought the in-ear CX 680 was more comfortable and fit better while my wife felt the CX was stable and comfortable. I thought the PMX sat at an awkward angle in my ear and wasn’t the most comfortable, on the contrary, my wife said they were the best headphones she has ever used for running.

For me, the CX earfins do seem to work well, keeping the CX in place better than a typical cable down IEM. With the PMX, once it is on, it is on! I think I could wear the PMX while sky diving without losing them… The CX has the option to remove the ear guides which allows them to be worn like any other IEM. Wearing them with the cable over the ears is a better option for me, but the cable strain relief is long which may make it difficult for people with smaller ears to wear that way.

Sound Quality: My wife’s first comment when using the PMX when coming from the ADDIEM was “these have bass!” While my wife did preferred the CX sound over the PMX sound, but with the combination of the comfort and secure fit, she would grab the PMX over the CX when she runs. I, on the other hand couldn’t get a great fit and thought the bass of the CX was more impactful, but to me both lacked depth.

CX: The CX sounds decent. Not great, but decent and listenable. There is a fairly good balance across the spectrum and before head-fi I would have been happy with the sound quality. However, there is a huge catch…microphonics, which was really bad for me. Even when putting the cable under my shirt and using the shirt clip I still had microphonics. Only when I wore them with the cable over my ear did the microphonics go away. But then the earfins are not usable. As far as overall sound quality, I would say these are somewhere between the V Moda Bass Freq and the metro.fi 220v in sound quality. Combine the V Moda detail level (kinda low) with the 220v balance (kinda nice).

PMX: For the price, for their intended purpose these sound OK. Not something I would keep in my ears for any extended period unless I was working out and didn't have anything else to listen to! I think the CX sounds much better, and my old Sony folding headphones also sound a little better, but don't stay on like these. May just be the fit in my ears, as there are o adjustments you can make, one-size-fits-all! The sound is mid forward but lacks mid clarity and detail with too much warmth and rolled off highs.

Now, my wife does think the CX sounds better, but doesn't think the PMX sounds as bad as I hear it. But then she doesn't have the discerning ear that I do, and the one-size-fits-all may play into her hearing something better than I am hearing.

Conclusion: So, you want tunes when you workout, are looking for durability, cool workout looks, something that will stay put, and has good sound. These will give you the durability, the looks, will stay put, but the weak link is the sound quality of both. The PMX due to the overall sound lacking detail and having too much warmth along with a lack of treble extension, and the CX due to cable noise. I would only recommend them to people that either focus on their workout, not the music, or are non-discerning listeners that want durability and something that really stays put during a workout.

@ mark - I forgot to mention the PMX does have a reflective strip on the back of the headphone band, so yes, you may be right! Unless you have long hair that covers it or someone comes at you from the side

But during the day people will be sure to know you are listening to headphones, thus reducing the amount of people that start to talk to you and wonder why you are not acknowledging them

I recently acquired the PMX 680 and will write a review of them within the next couple of weeks, and so I was especially interested to hear your take on them.

For the most part I agree with your assessment, although I only have about 6 hours of listening time with them so I don't have any final conclusions as of yet. I especially agree with your statement:

Quote:

"With the PMX, once it is on, it is on! I think I could wear the PMX while sky diving without losing them…".

I agree 100%!

Have you tried any IEMs with memory wires? I know that a lot of folks around here are not fans of the memory wires, but I found that they help quite a bit with keeping sweat from causing them to fall out while exercising. For example, I can wear my Meelec M6s for about a 45-min. run on the treadmill without them budging even a little bit. They stay planted in my ears with a nice, tight seal even when I sweat a lot.

To the OP: Did you try both pair while in the gym? From your review, I don't think you did. I just received the MX680 ear buds, and find that they don't work too good in a noisy environment, like the gym. They don't seal the ear to mask out ambient noise. I assume the PMX-680 is the same, since they are earbuds too. Also these MX680 have cable noise. I hear the cable noise if I move the cable.

Does the CX 680 plug the ear good, so you can listen to music at soft volumes? I would rather listen at soft volume, then to crank the MX680s at the gym.

To the OP: Did you try both pair while in the gym? From your review, I don't think you did. I just received the MX680 ear buds, and find that they don't work too good in a noisy environment, like the gym. They don't seal the ear to mask out ambient noise. I assume the PMX-680 is the same, since they are earbuds too. Also these MX680 have cable noise. I hear the cable noise if I move the cable.

Does the CX 680 plug the ear good, so you can listen to music at soft volumes? I would rather listen at soft volume, then to crank the MX680s at the gym.

First, I don't know how loud your gym is. Mine isn't all that loud other than weights clanking and treadmills moving. And no earbud will isolate well. Canalphone IEMs, while better, still aren't going to totally block out outside noise. Using foam tips will help, though. Deeper insertion IEMs such as the PFE or ER4P will offer more isolation than either the MX or CX and allow for the lowest volume with background noise.

As far as the cable noise, the CX does have a lot of cable noise, which IMO takes away from the good qualities it has for working out. The PMX does not have cable noise due to the headband that goes over your ears, but will not give you isolation.

Yes, I think with anything sealed you will hear that. Plus, for me the cable noise of the CX was an issue. I think the PMX is a better running headphone as you don't have a seal (so you will be able to hear your surroundings) and they stay put. But the SQ isn't on the same level as most headphones discussed on head-fi.